1. Field of the Invention
The present invention relates to a circuit breaker having an electronic circuit, and more particularly, to a constant voltage supplying circuit for a circuit breaker, capable of supplying a direct current constant voltage obtained by converting a wide range of alternating current input voltage (e.g. AC 100V˜460V) into a stable and constant small voltage to an electronic circuit section such as a trip controller, in the circuit breaker.
2. Background of the Invention
The present invention relates to a constant voltage supplying circuit for a circuit breaker, capable of supplying a direct current constant voltage to electronic components requiring low power consumption for a low-voltage circuit breaker having a rated voltage less than several hundred volts, or a low-voltage earth leakage circuit breaker, by converting an alternating current into a direct current.
In such a constant voltage supplying circuit for a circuit breaker, the following patent documents may be referred as the conventional art.
(Patent Document 1) KR10-2005-0040718 A
(Patent Document 2) KR10-1001768 B1
However, in case of a power supplying circuit according to the conventional art of the patent document 1, a constant current not a constant voltage is supplied to a circuit breaker. Further, a current is unnecessarily much consumed to a ground by a capacitor (indicated by reference numeral ‘C2’ in the patent document 1) connected to an output terminal for stabilization. This may lower power supply efficiency.
Further, in a constant voltage circuit according to the conventional art of the patent document 2, a resistor connected to an input terminal in parallel to a first transistor (the resistor indicated by reference numeral R11, etc. in the patent document 2), has a very large size. This may cause a large occupation area, a high price and high heat emission.